According to the Parkinson's Foundation, "People with vascular parkinsonism often experience a “lower body parkinsonism” and have trouble with walking and maintaining balance – much like people with classic Parkinson's," and though it mimics many Parkinson's disease symptoms, it not considered a progressive neurodegenerative disease.

In July of 2015, Bush had broken a bone in his neck after a fall in his home in Kennebunkport, Maine. He was also hospitalized for a week in December 2014 in Houston after being admitted for shortness of breath.

Former President George H.W. Bush, pushed by his son and former president George W. Bush, exits the funeral for his wife Barbara Bush at St. Martin's Episcopal Church in Houston. Jack Gruber, USA TODAY

Former President George H. W. Bush looks at the casket with his daughter Dorothy "Doro" Bush Koch as they wait for the mourners during the visitation of former first lady Barbara Bush at St. Martin's Episcopal Church on April 20, 2018, in Houston. Mark Burns, Pool Photo

Former President George H.W. Bush acknowledges the crowd at his presidential library on Nov. 11, 2014 before his son former President George W. Bush discusses his new book "41: A Portrait of My Father" in College Station, Texas. Bob Daemmrich, pool photo

Former president George H.W. Bush waves as he arrives at NRG Stadium before the NCAA Final Four tournament college basketball semifinal game between Villanova and Oklahoma in Houston on April 2, 2016. David J. Phillip, AP

Former president George H.W. Bush talks with Houston Texans owner Bob McNair before the first half of an AFC Wild Card NFL game between the Houston Texans and the Oakland Raiders on Jan. 7, 2017, in Houston. Eric Christian Smith, AP

Former president George Bush grimaces as he rubs his knee while he and former first lady Barbara Bush leave the field after she threw the ceremonial first pitch before the game between the Boston Red Sox and the Texas Rangers at Fenway Park in Boston on Aug. 10, 2005. Elise Amendola, AP

President Obama presents former president George H.W. Bush with the 2010 Medal of Freedom in the East Room of the White House Feb. 15, 2011, in Washington. Obama presented the medal to 12 pioneers in sports, labor, politics and arts. Chip Somodevilla, Getty Images

Former president George H.W. Bush watches the pregame warmup of the Houston Texans before their game against the Oakland Raiders in the AFC Wild Card game at NRG Stadium on Jan. 7, 2017, in Houston. Bob Levey, Getty Images

Former president George H.W. Bush receives a kiss from his wife, Barbara, as they arrive for the premiere of an HBO documentary on his life June 12 near the family compound in Kennebunkport, Maine. Charles Krupa, AP

Former president George H.W. Bush watches as his son, former president George W. Bush, throws the ceremonial first pitch of Game 4 of the World Series baseball game between the Texas Rangers and San Francisco Giants on Oct. 31, 2010, in Arlington, Texas. H. Darr Beiser, USA TODAY

Former president George H.W. Bush rides tandem with U.S. Army Sgt. Michael Elliott of the Golden Knights parachute team as he celebrates his 85th birthday on June 12, 2009, in Kennebunkport, Maine. Robert F. Bukaty, AP

Former presidents George H.W. Bush, left, and his son, George W. Bush, watch the warm-ups before an NFL football game between the Houston Texans and San Francisco 49ers on Oct. 25, 2009, in Houston. Pat Sullivan, AP

George Bush and President Bill Clinton gaze skyward as they watch the U.S. Army Golden Knights parachute team arrive during the dedication of the George Bush Presidential Library in College Station, Texas, on Nov. 6, 1997. Susan Walsh, AP

Bush gets some guidance from his wife, Barbara, as they clean a vacant lot along Germantown Avenue during the President's Summit on America's Future on April 27, 1997, in Philadelphia. Robert Deutsch, USA TODAY

Former secretary of State James Baker, left, and George H.W. Bush talk during the opening of the James A. Baker III Institute for Public Policy Annual Conference on Nov. 13, 1995, at Rice University in Houston. Pat Sullivan, AP

President Bush holds the badge of slain New York City patrolman Eddie Byrne during a speech at Attorney General Dick Thornburgh's anti-crime summit on March 5, 1991, in Washington. Marcy Nighswander, AP

President Bush speaks at the White House on Dec. 14, 1990 in Washington, D.C. Bush said he had offered 15 dates for Secretary of State James A. Baker III to visit Iraqi leader Saddam Hussein on or prior to January 12, three days before a United Nations deadline for Iraq to withdraw from Kuwait. Barry Thumma, AP

A 1950 photograph shows Barbara Bush, left, her husband, George H.W. Bush, and their son, George W. Bush, Dorothy Walker Bush and her husband, Prescott S. Bush, at the Odessa airport in Texas. The Bush family album

George H.W. Bush in his Yale University baseball uniform in New Haven, Conn. Bush was the first baseman on the Yale team that lost to California in the first College World Series in Kalamazoo, Mich. in 1947. AP